No there is not.
you can do about anything after you just cant beat the gym leaders again.
Yes, there is one... beat eight gym leaders
beat all the gym leaders to get the masterball beat all the gym leaders to get the masterball
Once you battle a gym leader you can not battle them again this is the same for all pokemon games unless you want to start the whole game over again but as soon as you get the badge you can't battle any gym leaders you already beat
If you beat all the gym leaders then you can try to beat the Elite Four, or you could go get the National Pokedex. (If you've beaten all the gym leaders, your doing pretty good!)
well you cant battle them again but in another Pokemon game you can and they are easy to beat and after you beat them you get like 6586 dollars cool huh?
you need to beat the Pokemon leuge and then get their phone numbers by asking or doing somthing in the town
Beat all the gym leaders.
The Gym Leaders challenge you again in the Survival Area, The BattleGround which is locked until Buck lets you in then you can VS them again!!
Just beat all the gym leaders.
You have to use a cheat.
Now, go and battle the Elite Four. Do what you would normally do after defeating the Gym Leaders. Though, using the cheat probably means you cannot get Kyogre because it involves the gym leaders.